440C Stainless Steel: The Hardest Household Alloy

 

What's unique about 440C's chemistry?​

It has 16-18% Cr, 0.95-1.2% carbon, and 0.5-1% molybdenum. High carbon gives it exceptional hardness after heat treatment.​

 

How hard is 440C compared to other steels?​

After aging, it reaches 58-60 HRC, harder than 304 (20-25 HRC) or 430 (25-30 HRC). Ideal for cutting tools needing sharp, long-lasting edges.​

 

Where is 440C typically used?​

Found in knife blades, bearings, and valve parts. Its hardness makes it perfect for wear-resistant, precision components.​

 

What about its corrosion resistance?​

Moderate-resists rust in dry settings but may tarnish in moisture. Better than carbon steel but less than 304.​

 

How is 440C heat-treated?​

Quenched at 1010-1070°C, then tempered at 150-315°C to balance hardness and toughness. Critical for achieving its signature strength.